Erl file not compiling due to syntax errors - erlang

Question

I am trying to figure out what is wrong with this code, cause it is giving me errors preventing it from compiling properly into a beam file. I do not see what is wrong with the syntax. Is there an IDE which could help me out?
These are the errors:
parallels#parallels-Parallels-Virtual-Platform:/var/backend/ejabberd_modules# erlc -I /var/tmp/ejabberd/src/ mod_stanza_ack.erl
./mod_stanza_ack.erl:97: syntax error before: '.'
./mod_stanza_ack.erl:98: syntax error before: Body
./mod_stanza_ack.erl:16: function route/3 undefined
./mod_stanza_ack.erl:3: Warning: behaviour gen_mod undefined
./mod_stanza_ack.erl:111: Warning: function strip_bom/1 is unused
./mod_stanza_ack.erl:114: Warning: function send_presence/3 is unused
./mod_stanza_ack.erl:120: Warning: function echo/3 is unused
./mod_stanza_ack.erl:123: Warning: function send_message/4 is unused
This is the code:
-module(mod_stanza_ack).
-behavior(gen_server).
-behavior(gen_mod).
-export([start_link/2]).
-export([start/2,
stop/1,
init/1,
handle_call/3,
handle_cast/2,
handle_info/2,
terminate/2,
code_change/3]).
-export([route/3]).
-include("ejabberd.hrl").
-define(PROCNAME, ejabberd_mod_stanza_ack).
-define(BOTNAME, stanza_ack).
start_link(Host, Opts) ->
Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
gen_server:start_link({local, Proc}, ?MODULE, [Host, Opts], []).
start(Host, Opts) ->
Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
ChildSpec = {Proc,
{?MODULE, start_link, [Host, Opts]},
temporary,
1000,
worker,
[?MODULE]},
supervisor:start_child(ejabberd_sup, ChildSpec).
stop(Host) ->
Proc = gen_mod:get_module_proc(Host, ?PROCNAME),
gen_server:call(Proc, stop),
supervisor:terminate_child(ejabberd_sup, Proc),
supervisor:delete_child(ejabberd_sup, Proc).
init([Host, Opts]) ->
?DEBUG("ECHO_BOT: Starting echo_bot", []),
% add a new virtual host / subdomain "echo".example.com
MyHost = gen_mod:get_opt_host(Host, Opts, "echo.#HOST#"),
ejabberd_router:register_route(MyHost, {apply, ?MODULE, route}),
{ok, Host}.
handle_call(stop, _From, Host) ->
{stop, normal, ok, Host}.
handle_cast(_Msg, Host) ->
{noreply, Host}.
handle_info(_Msg, Host) ->
{noreply, Host}.
terminate(_Reason, Host) ->
ejabberd_router:unregister_route(Host),
ok.
code_change(_OldVsn, Host, _Extra) ->
{ok, Host}.
% Checks a presence /subscription/ is a part of this.
% we may want to impliment blacklisting / some kind of
% protection here to prevent malicious users
%route(From, #jid{luser = ?BOTNAME} = To, {xmlelement, "presence", _, _} = Packet) ->
route(From, To, {xmlelement, "presence", _, _} = Packet) ->
case xml:get_tag_attr_s("type", Packet) of
"subscribe" ->
send_presence(To, From, "subscribe");
"subscribed" ->
send_presence(To, From, "subscribed"),
send_presence(To, From, "");
"unsubscribe" ->
send_presence(To, From, "unsubscribed"),
send_presence(To, From, "unsubscribe");
"unsubscribed" ->
send_presence(To, From, "unsubscribed");
"" ->
send_presence(To, From, "");
"unavailable" ->
ok;
"probe" ->
send_presence(To, From, "");
_Other ->
?INFO_MSG("Other kind of presence~n~p", [Packet])
end,
ok;
%route(From, #jid{luser = ?BOTNAME} = To, {xmlelement, "message", _, _} = Packet) ->
route(From, To, {xmlelement, "message", _, _} = Packet) ->
case xml:get_subtag_cdata(Packet, "body") of
"" ->
ok.
Body ->
case xml:get_tag_attr_s("type", Packet) of
"error" ->
?ERROR_MSG("Received error message~n~p -> ~p~n~p", [From, To, Packet]);
_ ->
echo(To, From, strip_bom(Body))
end
end,
ok.
%% HELPER FUNCTIONS
strip_bom([239,187,191|C]) -> C;
strip_bom(C) -> C.
send_presence(From, To, "") ->
ejabberd_router:route(From, To, {xmlelement, "presence", [], []});
send_presence(From, To, TypeStr) ->
ejabberd_router:route(From, To, {xmlelement, "presence", [{"type", TypeStr}], []}).
echo(From, To, Body) ->
send_message(From, To, "chat", Body).
send_message(From, To, TypeStr, BodyStr) ->
XmlBody = {xmlelement, "message",
[{"type", TypeStr},
{"from", jlib:jid_to_string(From)},
{"to", jlib:jid_to_string(To)}],
[{xmlelement, "body", [],
[{xmlcdata, BodyStr}]}]},
ejabberd_router:route(From, To, XmlBody).

Answer 1

./mod_stanza_ack.erl:97: syntax error before: '.' is saying the error is in line 97.
At line 97 change ok. to ok;. This will fix the issue.
Erlide plugin for eclipse is a good IDE to try out.

Answer 2

On line 97 in the function route/3 the first clause of the case is
"" ->
ok.
The . here ends the function which is illegal in the middle of a case, it should be a ;. This also means that the parser assumes that the variable Body on the next line starts a new function which is also illegal as a function name cannot be a variable.
Seeing the function route/3 has not been defined it cannot be exported which is the cause of the undefined function error on line 16.
Sometimes the compiler error messages are a bit cryptic but the line numbers usually help.